God, Hope & Helping Others
October 26 2012
By Dr. Mercola
A study on belly fat presented at the European Society of Cardiology Congress1, 2 confirms that visceral fat – the type that gathers around your internal organs – is far more dangerous to your health than you might think.
The traditional index of obesity, BMI (body mass index), has been proven to be terribly flawed as having a normal overall BMI and high abdominal obesity was found to be more dangerous than having a total BMI in the obese range.
For example, cardiovascular deaths in the study were 2.75 times higher for those of normal weight who had big bellies compared to those with both a normal BMI and a normal waist-to-hip ratio. It also implies that monitoring one's belly fat is more important than watching BMI.
According to Medical News Today:3
"Francisco Lopez-Jimenez, M.D., senior author and a cardiologist at Mayo Clinic in Rochestor, explained: 'We knew from previous research that central obesity is bad, but what is new in this research is that the distribution of the fat is very important even in people with a normal weight.
This group has the highest death rate, even higher than those who are considered obese based on body mass index. From a public health perspective, this is a significant finding.'
...Dr. Lopez-Jimenez wants readers to understand that even though their body mass index might be normal, it doesn't mean they have a low risk of heart disease. People can determine their risks by getting a waist-to-hip measurement, because where fat is distributed on the body can tell a lot, even if people have normal body weights."
There are a number of methods for calculating your ideal body size. The study above used waist-to-hip measurement. This is done by measuring the circumference of your hips at the widest part, across your buttocks. Then measure your waist at the smallest circumference of your natural waist, just above your belly button. Divide your waist measurement by your hip measurement to get the ratio.
The University of Maryland offers a handy online waist-to-hip ratio calculator you can use, which also tells you whether or not you might be at an increased risk for heart disease. The featured study used the following waist-to-hip ratio designations:
- Normal = 0.85 or below in women, and 0.90 or below in men
- High = 0.85 or greater in women, and 0.90 or greater in men
Another even simpler method to figure out if you have a weight problem is to measure only your waist circumference (the distance around the smallest area below the rib cage and above your belly button). Waist circumference is the easiest anthropometric measure of total body fat.
Either of these methods are far better than BMI for judging disease risk, as BMI fails to factor in how muscular you are. BMI also cannot give you an indication of your intra-abdominal fat mass.
Waist size, on the other hand, gives a good indication of the amount of fat you're carrying, particularly around the stomach area. Abdominal fat is considered an important risk factor for cardiovascular diseases such as coronary heart disease and stroke. Your waist size is also a powerful indicator of insulin sensitivity, as studies clearly show that measuring your waist size is one of the most powerful ways to predict your risk for diabetes. If you're not sure if you have a healthy waist circumference, a general guide is:
- For men, between 37 and 40 inches is overweight and more than 40 inches is obese
- For women, between 31.5 and 34.6 inches is overweight, and more than 34.6 inches is obese
Yet another tool, which many experts are now leaning toward as the most accurate measure of obesity, is body fat percentage. As it sounds, this is simply the percentage of fat your body contains, and it can be a powerful indicator of your health.
- Too much body fat is linked to chronic health problems like high blood pressure, high cholesterol, heart disease, diabetes, and cancer.
- Too little body fat is also problematic and can cause your body to enter a catabolic state, where muscle protein is used as fuel.
A general guideline from the American Council on Exercise is as follows:
Classification Women (percent fat) Men (percent fat) Essential Fat 10-13 percent 2-5 percent Athletes 14-20 percent 6-13 percent Fitness 21-24 percent 14-17 percent Acceptable 25-31 percent 18-24 percent Obese 32 percent and higher 25 percent and higher
Body fat calipers are one of the most trusted and most accurate ways to measure body fat. A body fat or skinfold caliper is a lightweight, hand-held device that quickly and easily measures the thickness of a fold of your skin with its underlying layer of fat. Taken at three very specific locations on your body, these readings can help you estimate the total percent of body fat within your entire body.
You can also use a digital scale that determines body fat, which is what I use personally. I use an Eat Smart Precision GetFit Body Fat Scale that I picked up from Amazon for around $50. Although many body fat measurements can be inaccurate, they are nearly all more accurate than BMI, and are particularly useful to determine whether you are gaining or losing fat. Although the absolute value may be off, the direction you are going (whether your body fat is going up or down) will be very accurate, and this is an incredibly useful measure of whether you're nearing your health goals or not.
Remember that it is FAR better to monitor your body fat percentage than it is your total weight, as the body fat percentage is what dictates metabolic health or dysfunction – not your total weight.
A recent study published in the Nutrition Journal4 has brought questions about the health impact of high fructose corn syrup versus sugar back to the fore. The authors claim their findings indicate there's no difference between regular sugar and high fructose corn syrup on weight loss. Dr. Richard Johnson, author of The Sugar Fix, and The Fat Switch (which I'll discuss in a moment), sent me the following rebuttal to share with you.
A recent study from James Rippe's group reported in the Nutrition Journal that low calorie diets caused equivalent weight loss regardless of the content of sugar or high fructose corn syrup. The study involved randomizing 267 overweight adults to receive low calorie diets containing either:
- 10 percent of the calories as sugar (sucrose)
- 20 percent as sugar (sucrose)
- 10 percent as high fructose corn syrup, or
- 20 percent high fructose corn syrup
Each group was given a diet calculated to reduce total calorie intake by 500 calories, and all groups were enrolled in an exercise program. At the end of 12 weeks all low-calorie groups showed similar decreases in weight. The authors concluded that the key aspect for weight loss is caloric restriction and not the content of fructose in the food. They also said that diets containing sucrose and high fructose corn syrup acted no differently from each other.
Let us address two issues that this study raises. The first question is whether it matters to reduce the intake of added sugars when you go on a diet. The second question is whether there is any real difference between table sugar (sucrose) and high fructose corn syrup.
- Does reducing sugar content matter? It is true that weight is largely governed by the law of thermodynamics, and that to lose weight the most effective way is to reduce food intake. This is why any diet that reduces calories will be effective at weight loss. However, reducing intake of added sugars, such as from table sugar (sucrose) or high fructose corn syrup (HFCS), does matter. These sugars contain fructose, and fructose has been shown to encourage weight gain because fructose can induce resistance to leptin, a hormone that controls appetite.
When fructose is fed to animals, they lose their ability to control their appetite. Restricting fructose intake can lead to a recovery of leptin sensitivity. This may be one reason low carb diets encourage weight loss, as they are essentially low fructose diets.
However, the problem with the study by Rippe is that all four diets consisted of an equivalent reduction in calories – so the benefit of reducing fructose on weight would have been largely obscured. However, we can see trends of a benefit – in that the two diets that contained 10 percent sucrose or HFCS showed a 3.3 and 4.15 kg weight loss, whereas the two diets that contained 20 percent HFCS or sucrose only had a 2.4 and 1.9 kg weight loss. This is likely because the diets lower in fructose were able to satisfy the appetite more effectively and likely did lead to some differences in energy intake.
Of greater concern is not weight, but the effects of fructose on body composition, fatty liver and insulin resistance. Fructose can rapidly induce metabolic syndrome and fatty liver that is not observed in animals fed the same number of calories as glucose or starch.
Weight gain is driven more by calories, but fatty liver and insulin resistance are driven more by fructose. In this study, the authors did not look at fatty liver or insulin resistance as outcomes. However, they did measure changes in fat percentage – again we see similar trends, with a reduction of 1.5 to 2.4 percent of fat in the 10 percent sucrose and HFCS groups, and a reduction of 1.1 to 1.3 percent of fat in the 20 percent sucrose and HFCS groups.
Thus, these studies suggest that reducing calories may reduce weight, but the content of fructose does matter.
Indeed, it is a shame that the authors did not include a hypocaloric diet with high sugar content. For example, some adolescents are ingesting 30 percent of their diet as added sugars. We found that laboratory rats given a diet of 40 percent sugar developed frank diabetes and fatty liver even when they were calorically restricted. We therefore need to rethink about the question of whether calories are just calories. Calories are important when it comes to weight, but the type of calorie can make a big difference on how it affects our risk for fat accumulation and diabetes.
- Are there differences between sugar and HFCS? The study by Rippe's group also implies that HFCS and sugar are relatively equivalent in their effects. For sure, both contain fructose and can induce metabolic syndrome and weight gain in animals. However, there are several differences that suggest that HFCS may be slightly worse.
First, soft drinks containing HFCS do contain more fructose than soft drinks with the equivalent amount of sucrose, in part because of the higher fructose content in HFCS. Our group found that this translates into higher blood fructose levels and higher blood pressure following ingestion. More recently, Michael Goran's group found that the percentage of fructose in HFCS-containing drinks is often higher than labeled, and may contain as much as 65 percent fructose.
Second, there may also be differences in how the fructose is absorbed between the two drinks. Thus, HFCS may result in faster absorption of the fructose since the fructose is not bound, whereas sucrose must first be degraded to glucose and fructose in the gut before it is absorbed. Our group found that mixtures of fructose and glucose led to worse fatty liver in laboratory animals than equivalent amounts of sucrose. Clearly more studies are needed, but the evidence does suggest that there are likely biological differences in these two added sugars.
In summary, we would recommend reducing intake of added sugars, both from sucrose and from HFCS, in any dietary plan. Reducing natural fruit intake is less necessary for while these fruits also contain fructose, they also contain many excellent nutrients that help combat the effects of fructose. More studies are needed to determine if the biological differences between HFCS and sucrose are clinically important.
If you have ever struggled losing weight and keeping it off, you already know what a challenge that can be. Dr. Johnson's new book, The Fat Switch, presents a groundbreaking approach to preventing and reversing obesity. Dr. Johnson asked me to publish his book to help spread the word and we hope to do just that. It's the first book we've published that I did not write, because I felt it shared a powerful message on a very important topic that is central to the work we teach on this site.
I firmly believe that understanding how fructose influences your fat metabolism by activating your "fat switch" is key for achieving optimal weight and health. According to Dr. Johnson, based on his decades of research:
"Those of us who are obese eat more because of a faulty 'switch' and exercise less because of a low energy state. If you can learn how to control the specific 'switch' located in the powerhouse of each of your cells – the mitochondria – you hold the key to fighting obesity."
I highly recommend picking up a copy of this book, which has been described as the "Holy Grail" for those struggling with their weight. In it, Dr. Johnson explains the details behind these five basic truths:
- Large portions of food and too little exercise are not solely responsible for why you are gaining weight
- Metabolic Syndrome is a normal condition that animals undergo to store fat
- Uric acid is increased by specific foods and causally contributes to obesity and insulin resistance
- Fructose-containing sugars cause obesity not by calories, but by turning on the fat switch
- Effective treatment of obesity requires turning off your fat switch and improving the function of your cells' mitochondria